When it comes to my mobile games, I favor simplicity of structure above almost all else. Something to play on the train, in a dentist waiting room, in those few moments in bed before sleep, in which no real thought is required beyond the instantly dismissible attention time required to solve a puzzle—be it lexical, spatial, or otherwise. From Tetris to Candy Crush to Word Cookies and more, my addictions are fairly straightforward and easy to explain. True, thousands of apps try for this magically simplistic formula and fall short; so imagine my joy when I happened upon Happy Glass, one of the most basic yet fulfilling games I’ve yet encountered.

The setup couldn’t be more intuitive. You’re presented with a frowning glass, a spigot that will release a set amount of water, and one or more obstacles or potential tools. Your mission: Get the water to run into the glass until it crosses a certain threshold, triggering a smile of the face of your little anthropomorphic container. You’re allowed to draw lines that turn into tangible matter, and that’s it. Got a glass sitting on the opposite side of the screen from your spigot? Draw a gentle slope from one to the other. Got a brick ready to fall into your glass, preventing water from getting in? Design a basic fulcrum to push it out of the way, allowing the water ready access. It reminds me somewhat of Lemmings, if you had only one tool to direct your lemmings to safety. I can’t tell you how many hours of blissfully empty-headed pleasure I’ve gotten from allowing my brain to turn off and focus solely on the calming process of funneling water to its proper holder; there’s a Zen beauty to it (as with many of the best mobile games) that relaxes you even when you get stuck on a more complicated level. (Acquiring gold to get hints for completing ones that stump you is easy, by the way.) I’m already looking forward to the next time my train to work gets delayed for a precious few extra minutes.